The common assumption is that a rear-end collision resulted from the rear driver following the front vehicle too closely, or tailgating. Some states apply a rebuttable presumption to this situation, which places the burden on the rear driver to show that they did not cause the accident by following too closely. However, sometimes a collision results from defective brakes in the vehicle of the rear driver. This defense often raises suspicions, but it can be effective if it is made promptly and persuasively. The rear driver would need to mention the problem with the brakes in the immediate aftermath of the accident. If they raise it after a claim has been filed, this likely will be a losing argument because it will look like an excuse.
You should not drive away from the accident scene if you are arguing that defective brakes caused the crash. It would be dangerous to continue driving a car with defective brakes, so driving away will undermine the credibility of this defense. Instead, you should arrange for your car to be towed to a garage so that the condition of the brakes can be evaluated.
Inspection of the Vehicle
You should arrange for a prompt inspection of the car and the brakes by a mechanic. The tow truck can take it directly to the repair shop. Drivers who mention a problem with the brakes but ask for the car to be towed home probably will lose credibility. You should make sure that the mechanic is neutral, rather than a friend or acquaintance. They may be interviewed during the litigation process, and they may need to testify on your behalf at trial.
The cause of the brake failure needs to be obvious to the mechanic. It probably should be an issue that is visible and not extremely unusual. For example, perhaps a component of the brakes was broken or dislodged. An argument that the brakes failed because of a complex or rare issue that is hard to describe may not be persuasive to an insurer or a jury.
When Liability Remains with the Rear Driver
The brake failure must have been unforeseeable for the rear driver to avoid any liability for the accident. If the driver already knew that the brakes were faulty, they should have taken the vehicle to be repaired rather than going out on the road. Being a safe driver involves not only acting safely behind the wheel but also keeping up with maintenance on the vehicle. A lack of attention to a safety issue like faulty brakes can result in liability for both the driver and the owner of the car, if those are different people.
Also, the brake failure must have been so complete and unexpected that the driver could not take steps to mitigate or prevent the collision. If the driver failed to notice the problem with the brakes when a reasonable driver would have noticed it, or if the driver was following too closely to stop even with properly functioning brakes, they still may be at least partly liable for the accident.